PROJECT SUMMARY/ABSTRACT The purpose of this cooperative agreement is to support a network of sites that provide surveillance and data collection on new vaccine use, the impact of the new vaccines and upcoming vaccines and other immunoprophylaxis, new vaccine policies and policies under consideration, through enhanced inpatient and emergency department (ED) surveillance, applied epidemiologic research, and investigator-initiated investigations. This New Vaccine Surveillance Network (NVSN) will address the Healthy People 2020 priority area for immunization and infectious diseases, specifically, the reduction or elimination of vaccine preventable diseases and evaluating vaccination coverage for universally recommended vaccines. The intent of the NVSN program is to utilize a network of population-based sites to conduct active surveillance for acute gastroenteritis in addition to providing a framework in which to study other important vaccine related questions. The major focus will be to describe the burden and epidemiology of rotavirus infection resulting in hospitalization and ED visits between 15 days and 11 years of age using active surveillance for acute gastroenteritis. Active surveillance for acute gastroenteritis will be conducted in 2 settings (hospital and ED) to determine the disease burden of acute gastroenteritis and rotavirus in each of these settings and to examine trends over time (pre- and post-licensure). Children <11 years of age hospitalized or cared for in the ED with symptoms of AGE will be screened, invited to participate if they meet eligibility criteria and consented for the study. Demographic and clinical data will be collected on all enrolled children. A stool specimen will be collected and tested for rotavirus. Data will be analyzed to estimate population-based rotavirus hospitalization and ED visit rates, to characterize the clinical and epidemiologic factors of children with acute gastroenteritis due to rotavirus, to utilize rotavirus cases obtained through this study to conduct applied epidemiologic evaluations of the effectiveness of rotavirus vaccines and costs of rotavirus disease and to examine the burden of other pathogens such as norovirus using the well characterized data and specimens obtained through this surveillance system.